User devices (e.g., smartphones, tablet computers, etc.) may enable users to communicate with one another via a network (e.g., a wireless telecommunications network, the Internet, etc.). Some network service providers may enable users to associate a smartphone with other user devices so that the user may make calls using any of the user devices as though the call was being made from the smartphone. Additionally, some service providers may enable the user to switch between user devices during a call. For instance, during a call initiated with a tablet computer, the user may have the call transferred to the user's smartphone.